Conventional digital x-ray radiographic imaging systems record a representation of the attenuation that x-rays experience while traversing a medium. Detector options include integration, photon counting, and energy resolution capability in geometric configurations that include slit, slot, small area, and full field of view imaging formats. The development of effective image contrast enhancement techniques for digital radiography has taken various forms: optimizing the x-ray source emission spectrum, employing more efficient detectors and detector with photon counting or spectroscopy capability (Nelson, U.S. Pat. No. 4,937,4534), introducing contrast materials into the subject (for example, the human body), using analyzers (Nelson, U.S. Pat. No. 4,969,175) with coherent synchrotron sources (DEI) and using small (for example, a micro-focal spot) x-ray radiation source alone or in conjunction with a coded aperture to exploit phase contrast imaging (PCI). The contrast gains achieved with PCI typically improve as the source size decreases and/or the unshielded (active) detector pixel size decreases. PCI limitations typically include reduced tube output as focal spot size decreases and reduced detection efficiency if the active pixel area is reduced. The benefits of PCI imaging compared to attenuation imaging tend to be more pronounced for imaging of small structures or nonuniformities within an object. Hence, x-ray radiation detectors that offer high spatial resolution are typically employed. PCI images, as with conventional digital x-ray images, suffer from the effects of attenuation (absorption, scattering) and variable magnification for a thick object, as well as from the effects of overlapping structures and nonuniformities in the object. An object such as a breast with a complex tissue structure may represent a challenge in that the contrast gains derived from PCI may also generate unexpected artifacts. There are other sources that may contribute to image (signal) degradation that tend to be present in x-ray radiographic imaging systems. Radiation crosstalk effects between detector elements and radiation loss effects from detector elements (due to scattered x-rays, characteristic x-rays, bremsstrahlung x-rays, Compton electrons and photoelectrons, and optical photons if applicable) as well as detector element electronic noise and electronic crosstalk effects between detector elements can effect the final image quality. Conventional digital x-ray radiography dominates the medical, industrial, and scientific markets at this time with the expectation that PCI systems may be competitive in the future for specific applications. A commercial clinical mammography (mask-less) PCI system (see Morita T, et al., Lecture Notes in Computer Science, 5116, p. 48-54, 2008) with a microfocal spot x-ray tube source (approximately 100 micron focal spot size) that employs magnification (which contributes to scatter reduction) has experienced limited success due to the modest improvements obtained in contrast enhancement of small structures. A smaller focal spot improves contrast enhancement but at the cost of longer exposure times (creating a concern for patient motion issues). PCI devices (see Oliva A, et al., Nucl. Instru. Meth. A, vol. 610, p. 604-614, 2009; Munro P, et al., Phys. Med. Biol., vol. 55, p. 4169-4185, 2010; Keyrilainen J, et al., Acta Radiologica vol. 8, p. 866-884, 2010) with coded apertures (which also use magnification) that are currently undergoing development deploy pre-object and pre-detector masks. The pre-object mask creates microbeams wherein each microbeam illuminates a fraction of each detector element or pixel in a linear array (1-D) or a single detector element (2-D). The pre-detector mask (shading a fraction of each detector element and/or the region between detector elements from incident radiation). Alignment of pre-object and pre-detector masks with an array of discrete detector elements is challenging. Rigid pre-object and pre-detector masks (apertures) are typically designed with a “fill-factor” which represents the fraction of the aperture that is open to transmit radiation. If the fill-factor is zero then dark field images can be acquired. The illuminated detector element or pixel fraction can be varied by changing the relative position (overlap) of one mask with respect to the other. High spatial resolution detectors are particularly useful since the problem of “spill over” of a pixel signal into adjacent pixels can be reduced for a particular imaging application. Preferably, the pre-detector mask is positioned close to the detector and the mask materials heavily attenuate the incident radiation (using x-ray radiation of a suitable spectrum along with one or more dense, moderate-to-high atomic number mask materials such as Cu, Ag, W, Pb, Au and U). There is a contrast benefit if individual microbeams overlap their corresponding detector masks (albeit with an increase in patient dose). If a fraction of the active area of a detector element is shaded from x-rays then this electronically-active fraction can contribute to the total detector element readout noise due to the radiation effects and sources of electronic noise mentioned previously. Focal spot sizes less than 100 microns have been tested with experimental 1-D and 2-D coded aperture PCI designs.